A radio-frequency module of an existing radio-frequency device, for example, a base station (BS), is generally formed by a plurality of single boards, such as transceiver (TRX) single board, low noise amplifier (LNA) single board, power amplifier (PA) single board, power supply single board, and cavity duplexer. Such a radio-frequency module formed by a plurality of single boards is disadvantageous in competition in terms of realizing miniaturization, low cost, high reliability, and easy assembling and maintenance.
At present, the solutions of designing two or more single boards in the radio-frequency module on the same board have also emerged, for example, designing a TRX and an LNA on the same single board, designing a PA and a power supply module on the same single board, or even designing a low-power PA (for example, lower than 60 W), a TRX, an LNA, and a power supply module on the same single board. The implementation of such solutions may improve the competitiveness of the radio-frequency device.
For example, the following single board sharing and laminating design solutions exist in the prior art.
(1) Laminating Design with at Least Two Single Boards
In such a solution, a PA is designed as an independent single board, or the PA and a power supply module are designed on the same single board, and the other modules (for example, a TRX module and an LNA module) are designed on the same single board or separate single boards.
Such a solution can easily meet the ground loop and heat dissipation requirements for the PA. As the area of the PA is not large, the single board of the PA may be made of a radio-frequency board material or formed by pressing the radio-frequency board material with an ordinary board material, and single boards of the other modules may be completely made of an ordinary board material, so that the total cost of a PCB can be effectively controlled. In addition, since at least two single boards are adopted in the solution, a total area of the single boards is enlarged, so that more designing resources for the layout and wiring are provided for the PCB design, and the flexibility of the design solution is improved. However, during the process of implementing the present invention, the inventors found that, in such a solution of the prior art, as radio-frequency signals and power supply and control signals between the single boards are realized through connectors, cable connection, or blind-mate connection, the material cost and assembling cost are increased, and the risk of poor reliability is increased.
(2) Single Board Sharing Design of Low-Power PA
Currently, as for the solution of a single board sharing design between a low-power PA and the other modules, mainly a 1+n+1 laminating solution by using a low-cost board material and a high density interconnection (HDI) technology is usually adopted. In some radio-frequency devices, an LNA and a duplexer are disposed externally, and a PA, a power supply module, and a TRX are integrated on the same single board. In this case, a power amplification tube of the PA is partially sintered or mounted by using screws. Such a solution is applicable to low-frequency low-power PAs. Non-ground holes thereof are just opened to the last but one layer, which is favorable for shielding and heat dissipation. Meanwhile, the structure is simple and the cost is low. The HDI board facilitates the realization of outlet in a few layers of a high-density ball grid array (BGA), and the material cost is low. In addition, if the power amplification tube is mounted by using screws, the assembling process is quite simple.
However, during the process of implementing the present invention, the inventors found that, in such a solution of the prior art, as the signal loss of the low-cost board material is far higher than that of the radio-frequency board material, such a solution is not applicable to high-frequency high-power situations. In addition, as the HDI technology is adopted, the PCB manufacturing cost is higher than that in the plated through hole (PTH) technology. Moreover, the HDI technology cannot be implemented by pressing radio-frequency board materials. As only holes with a limited depth (for example, less than 5 mil) can be formed by laser drilling, and most radio-frequency board materials are not suitable for performing laser drilling.
(3) Embedding Design of Power Amplification Module
In such a solution, a PA, a power supply module, and a TRX are designed on the same single board to form a laminated single board. The large PCB may be completely made of a low-cost board material, and may adopt the 1+n+1 laminating mode by using the HDI technology. In this case, a peripheral circuit of the PA is designed on the large PCB, and a matching node and an output portion of the PA adopt an embedding design. In such a solution, as the power amplification tube and the high-power output circuit portion are separately designed as an independent module by using a high-performance radio-frequency board material, and the module is soldered on the large PCB or interconnected to the large PCB by using a suitable connector, and thereby the solution meets the consistency and reliability requirements of the high-frequency PA, and meanwhile meets the requirements of high-power applications. In addition, the solution also achieves the advantages of being favorable for shielding and heat dissipation, and having a simple structure, and a low cost.
However, during the process of implementing the present invention, the inventors found that, in such a solution of the prior art, as the PA adopts an embedded module, a particular connector is required to connect the power amplification module with the large PCB, so that the complexity and cost of the manufacturing and assembling processes are increased. If the module is soldered on the large PCB by reflow soldering, the risks of poor soldering and poor reliability of solder connection may be caused due to the coplanar fitting problems. As the large PCB adopts the HDI technology, the manufacturing cost of the PCB is rather high. In addition, the embedded module is not suitable for the realization of a large-size PA. In addition, as the external shape of the PA module needs to cater to the design requirements of the large PCB, the compatibility of the PA module is deteriorated, resulting in complex material relations, thereby increasing the peripheral costs of assembling, material maintenance, and the like.
All of the above solutions in the prior art have defects. In addition, due to various reasons, in some radio-frequency devices, the demand for a high-power PA (for example, higher than 80 W) is increasingly large. However, the above solutions fail to integrate all the high-power PA, the LNA, the power supply module, the TRX, and other circuits on the same single board, that is because the process of designing the high-power PA and the other modules on the same single board needs to meet requirements in many aspects, including loss, pin count, heat dissipation, single board thickness, partial sintering, warping control, interconnection among single boards and modules, assembling, and the like.